At the time of my and my sister's birth, my mother was not a citizen of the USA yet, their law, made us, automatically citizens at the time of birth under their law....if she had pledged her allegiance to the Usa, and been a citizen of both the USA and Italy, then our citizenship would not have been automatic, and she would have had to apply for naturalization papers to make us citizens of Italy... is again my understanding, of the laws at the time we were born.
My mom didn't want us to get citizenship of Italy, reporting to them our birth and their laws did it. My mom would not even speak Italian to us, because she was ignorant on children learning languages when young and was afraid to speak it to us, making us confuse languages....she was wrong, we could have handled learning both...but she just wanted us to learn and speak English....just wanted us to know with certainty, the language spoken here...in America
(My mom spoke and wrote English fluently when she met my dad and married him overseas, and 5 other languages)
The writers of the 14th amendment made it clear that in their other writings, that it was meant for all persons, with few exceptions like Diplomats and their family members.... if it were meant for just slaves, as you see it...then there would be no need to put in, under the jurisdiction of the USA law part. It was put in with purpose, and distinction.